1. Field of the Invention
The invention disclosed herein relates generally to printer ribbon supply spools, and more particularly to a core and hub system for securing ribbon supply spools to printers.
2. Background of the Invention
In the field of printer technology, a number of different methods have been developed for applying ink to paper, cards, or other print media in a controlled environment. In addition to standard ink ribbons and hammers as are known in the art, various other printer technologies have also been developed, such as, for example, direct thermal and thermal transfer printing. Although the different printer technologies may differ from each other in significant ways, the different technologies typically have at least two things in common: (i) they typically involve a controlled transfer of the print substance from a substrate onto the print media, and (ii) the act of printing depletes the print substance so that the substrate must periodically be replaced. Accordingly, replaceable ribbons, supply spools, and take-up spools are commonly used in many different types of printers. The term ribbon, as used herein, refers to any type of printer technology that employs a flat, linear material wound around a spool.
Ribbon/spool combinations are usually sold as a single item. Spools are also known as cores. Typically, each core is mounted on a spindle, or hub, for operation, the hub being generally cylindrical in shape and attached to a motor-operated assembly that accurately controls the rotation of the core and ribbon. Since the printer ribbons are required to be replaced, most printers that use ribbons mounted on cores are designed such that the core containing the ribbon can be replaced. It is preferable that such replacement can be completed by a non-technical operator, without the use of tools and with minimal instruction. Accordingly, the design of the core/hub assembly must be such that aligning and inserting the core on the hub and securing the core to the hub are easily performed. Additionally, the interface between the hub and a mounted core should be firm enough to keep the core (and associated ribbon supply) accurately controlled during operation of the printer.
Thus, there exists a need for a core/hub assembly that provides for easy alignment and insertion, and provides for a secure interface to prevent slippage of the core during printer operation.
The present invention is directed to a core/hub assembly that provides for easy alignment and insertion, and provides for a secure interface to prevent slippage of the core during printer operation.
In accordance with the present invention, a hub includes keys mounted at a proximal end which serve to transmit torque when engaged with a core. The hub further includes splines configured to be received within a core and provide longitudinal support thereto. A core includes a plurality of longitudinally extending ribs that cooperate to form channels configured to receive the splines of the hub. A portion of the ribs include compliant radially oriented leaf springs at one end which center the core on the hub and provide a physical fit of the core on the hub by engaging the keys at the proximal end of the core when properly inserted therein. The core/hub assembly configuration provides for simple loading of the core on the hub and maintains a secure interface between the core and hub to prevent slippage during use.